package com.lam.common.components.easyexcel.handlers;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.poi.ss.usermodel.Cell;

import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;
import com.lam.common.utils.CollectionUtil;

/**
 * 设置自适应列宽
 */
public class AutoColumnWriteHandler extends AbstractColumnWidthStyleStrategy {

    private static final int MAX_COLUMN_WIDTH = 255;

    private Map<Integer, Map<Integer, Integer>> cache = new HashMap<>(8);

	@Override
    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<WriteCellData<?>> cellDataList, Cell cell,
            Head head, Integer relativeRowIndex, Boolean isHead) {
        boolean needSetWidth = isHead || !CollectionUtil.isEmpty(cellDataList);
        if (!needSetWidth) {
            return;
        }
        Map<Integer, Integer> maxColumnWidthMap = cache.get(writeSheetHolder.getSheetNo());
        if (maxColumnWidthMap == null) {
            maxColumnWidthMap = new HashMap<>();
            cache.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);
        }
        Integer columnWidth = dataLength(cellDataList, cell, isHead)+1;
        if (columnWidth < 0) {
            return;
        }
        if (columnWidth > MAX_COLUMN_WIDTH) {
            columnWidth = MAX_COLUMN_WIDTH;
        }
        Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());
        if (maxColumnWidth == null || columnWidth > maxColumnWidth) {
            maxColumnWidthMap.put(cell.getColumnIndex(), columnWidth);
            writeSheetHolder.getSheet().setColumnWidth(cell.getColumnIndex(), columnWidth * 256);
        }
    }

	private Integer dataLength(List<WriteCellData<?>> cellDataList, Cell cell, Boolean isHead) {
        if (isHead) {
            return calcColumnWidth(cell.getStringCellValue());
        }
        WriteCellData<?> cellData = cellDataList.get(0);
        CellDataTypeEnum type = cellData.getType();
        if (type == null) {
            return -1;
        }
        switch (type) {
            case STRING:
                return calcColumnWidth(cellData.getStringValue());
            case BOOLEAN:
                return 3;
            case NUMBER:
                return (int)(cellData.getNumberValue().toString().getBytes().length*1.6);
            default:
                return -1;
        }
    }
    
    private int calcColumnWidth(String str){
    	return str.getBytes().length/2 + (int)(str.length()*1.5);
    }
}
